The invention concerns the seal between the rotating and the stationary parts of a mill which is flowed through by air, particularly at excess pressure, and provided with a barrier air chamber which is connected through a gap with the interior space of the mill.
Seals of that kind are for example used in cylindrical millstone mills between the bedstone and the mill housing (Aufbereitungs-Technik 1971, Volume 9, page 543). The gap is in this case so formed that the barrier air flows through the gap upwardly from below. Under unfavorable operating conditions, dust-charged air out of the interior of the mill can in that case penetrate into the barrier air chamber where the dust deposits.